Rotary radial plunger hydraulic apparatus



April 26, 1938. E. K, BENEDEK I ROTARY RADIAL PLUNGER HYDRAULIC APPARATUS Filed May 28, 1935 3 Sheets-Sheet l,

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ma N m :L K, K u f/ 5 sheets-sheet 2 April 26, 1938. E. K. BENEDEK ROTARY RADIAL PLUNGER HYDRAULIC APPARATUS Filed May 28, 1935 April 26, 193s. E. K. BNEDEK 2,115,296 i r ROTARY RADIAL PLUNGER HYDRAULJC/Jv APPARATUS Filed May 28, 1935 :s sheets-sheet s INVENToR #1 ATTORNEY LEKKEENEDEK' Patented Apr. 26, 1938 l ROTARY PATE-.Nr OFFICE APPARATUS Elek K. Benedek, Bucyrus, h10 Application Mayes, 1935, serial No. :assi W claims. (ci. 10%161) v Y This invention relates to hydraulic pumps, motors and transmissions'of the rotary radial plunger type and particularly to an improved load transmitting means between the plungers and the 5 plunger actuating reactances thereof. v

Two general types of hydraulic mechanisms have been used heretofore each of which has certain advantages over theother, but both have features which render them unsatisfactory for high speeds and for usev yunder high hydraulic fluid pressures.

The first type employs arotary reactance which rotates concurrently with a plunger carrying barrel about an axis eccentric to the barrel axis 16 and atthev-same angular velocity, while cooperating with the plungers, slight circumferen-y tial oscillation of the reactance relative to the plungers'compensating for tangential components of eccentricity of the rotary reactance and barrel.`

20 At high speeds, it becomes necessary to mount a rotary reactance anti-frictionally so as to reduce the torque requiredfor driving the reactance and to provide efficient load transmission. At the high pressures, any anti-friction mounting of the reactance` preferably-shou1d be ar- A ranged in radialL alignment with the vhydraulic load transmitting means of the plungers so that the hydraulic load is delivered directly and the anti-friction mountingis subjected only to compressive stresses due to. load:

a largeA diameter anti-friction assembly.v `When high speeds and'high .pressures are`combined, however, the advantages of this type of reactance are offset by thehi'gh rotative speed of the antifriction assembly so arranged in radial alignment i with the load transmitting means. r In fact, the

rotative speed becomes so great that an antifrictionlassembly so arranged' and capable of Withstandingthe speed without excessive fric- 40 tional heating and consequent failure is'diil'- cult to provide. Likewise, excessive centrifugal and inertia forces are developed. Consequently,

" far high pressures and 'speeds combinedvthe sta.-l

tionary reactance types yof mechanisms are utilined with somewhat better results.

While-rotary reactancepumps and motors are successful commercially up to a. certain size, above such size they areimpractical due tothe rapid.,

increase of their cost of manufacture. For sizes .F0 utilizing standard complete' anti-friction lbear-- ings, for example, a bearing of 12' inner diameter may beobtained for commercial prices and will perform at` commercial speed. However,

' above these sizes the bearings are guaranteed 55 and rated only forspeeds and loads which-are This necessitates less than those required for high speed operation comparable to thespeeds ofthe smallersze pumps and their bearings. For'higher delivery and speeds such as 200 I-I. P. and 900 to 1,000 R. P. M. bearings cannot be obtained at com- A45 mercial prices, but only on special yorder and at an almost prohibitiveprice. 'I'he art of making these bearings is insuiliciently developed with.

`the resin: 'that' the manufacturer, even whne asking an almost prohibitive price therefor, is 10 unable to specify or approve the performance o f Y the bearing assembly for thehgh speed application necessary to be withstood, apparently because of lack of experience'and data as to the working of such bearings. The manufacturers 15 construct the large bearings 'on the .same prin-A cipl'es as small size standard bearings are con.- Y

structed, but the art `of manufacture of smaller standard bearings, when Vso applied in making the larger bearings for proportionate speed and load' 20.

performanceV results in bearings which rapidly overheat and burn out at peripheral speeds of' from 5,000 to .10,000 'feet per minute. The heating of bearings above standard sizes, bunt in accordance 'to the specifications of the smaller 25 bearings, is further aggravated by the fact .that larger bearings require greater radial press t on a much heavier driving member, withthe con.- sequence` of radial elastic expansin and additional tightening of the races on the anti-friction elements. It is not known exactly how much of the press fit goes into the driving'member and into radial expansion `of the inner bearing race, but I found in practical application that the radial clearance in larger bearings Lmust be about 35 ten times greater .than'provided in' conventional Another serious disadvantage in connection with larger and'high speed bearings of the commercial type is the' fact thatfailure of v'any one 40 element `or part of the bearing assembly causes rapid destruction 'of' the entire assembly or so 1 damages 'some portions'of the race that the remalnder of the very expensive assembly must be discardedlV Furthermore, in event of breakage 45 of any` roller or race'element the Vparts drop into the high Speed pump structure, additionally damaging'the'same. i Y

lIn the stationary reactance type of pump or motor this large, bearingassembly is eliminated. However, the --load transmitting elements` between the plungers andthe stationary re'actance` must roll eilici'ently vabout the circumference of the reactance if they are'to take the place of the eliminated large anti-friction bearings of a rollili tary reactance structure, on a favorable competitive basis with respect toy useful life and specic output of the machine. The speed of complete rotation of the transmitting elements about their own axes and bearing surfaces is becoming so great that it is difficult to maintain them in proper lubricated and free rolling condition and at the same time of sumcient 'load bearing capacity. Furthermore, vonly a very limited space can be provided in the plunger heads for accommodatingthe load transmitting elements if a reduced competitive overall radius of the mechanism is to be retained and the mass of the parts is to be kept sufficiently small to prevent ineffi-A ciency and damage to thevparts due to excessive centrifugal and inertia forces.

It must be borne in mind that in the stationary reactance type of machines, the load transmitting means must concurrently roll and rotate at high speed, revolve with the pistons and barrel, and reciprocate'atr high speeds while transmitting heavy hydraulicloads. These combined factors render difcult the provision of proper bearing means between the load transmitting elements and the stationary reactance sufficient to insure that the load transmitting elements will roll and not slide on the reactance and will withstand, while rolling and rotating lthe extremely heavy hydraulic loads. Heretofore a satisfactory solution has not been made of this problem which requires simultaneous consideration of all the requirements of a durable'and efficient machine.

A distinct advantage resides in the utilization of a stationary reactance in the structure herein described in that in event of failure of any one or part of the rolling load transmitting elements, only the part failing need b e replaced and this can be done readily at a very small cost and the possibility of damage to any other part of the mechanism thereby isV extremely remote.

The present invention has to do with antifriction load transmitting elements operatively connecting the plungers and stationary reactance by virtue 'of which, rst, the reduced overall diameter of the mechanism may be retained, so as to reduce the circumferential distance over which the elements must rolifor each revolution of the barrel, and, second, the rotational speed of the transmitting elements with respect to each other 'and-to the cooperating plunger surfaces are maa reactance' and plunger by which free anti-fric-v p tion rolling engagement between the plunger and the stationary reactance is eected.

A correlative and equally important object is to reduce the rotational speed of the parts of the load transmitting elements with respect to each other and to the associated supporting surfaces K of the associated plunger.

Other objects are to'accomplish these results without increasing the size and weight of the working parts and while providing adequate load transmitting capacity between the plungers and reactance. l

Other objects and advantages will become apparent from the following description wherein reference is made to the drawings in which Fig. 1 isa horizontal longitudinal sectional view of. a transmission mechanism embodying the principles of the present invention;

Figs. 2 and 3 are vertical cross sectional views taken on planes indicated by the lines 2--2 and 3--3 respectively of Fig. 1, part thereof being taken on lines 2a-2a and Brt-3a respectively for clearness in illustration;

Fig. 4 is a vertical sectional View of a pump or motor of a hydraulic transmission, illustrating a modified coupling between the plungers and the reactance; A l.

Fig. 5 is a vertical sectional viewof the pump illustrated in Fig. 4 and is taken partly on line 5-5 and partly on line 5a-5a, of Fig. 4; and

Fig. 6 is an enlarged fragmentary longitudinal sectional view of the load transmitting elements of the pump or motor of Fig. 2.

Referring to Fig. 1, the invention is shown, for illustrative purposes, as embodied in a transmission comprising a casing I having a valve pintley 2 on the ends of which are mounted respectively a pump barrel 5 and a multi-stage motor barrel 6, the transmission being of the multi-stage type such as more fully described and claimed in my copending application, Serial No. 22,259, tiled May 18,1935. Since load transmitting elements between the plungers and reactance are thesame regardless of whether the structure is vused in a pump or motor, the largest motor stage only will be described in` detail, the corresponding parts of the smaller motor stage being apparent therefrom. y

The barrel 6 is rotatably mounted in the casing f I for rotation about the axis of the corresponding end of the pintle 2, which fits the axial vbores of the barrel and is provided with suitable valve ports cooperable with the barrel cylinders for valving relation, as more fully described in said copending application. Within the casing I and surrounding the barrel 6 is a stationary reactance 'I having its axis parallel to the rotative axis of the barrel 6. The barrel is provided with a plurality of radial cylinders 8 in each of vwhich is received a reciprocable plunger 9 having an enlarged head portion I0 at its outer end. The heads I0 of the plungers are reciprocable with the associated plungers radially of the barrel in radial guideways II formed in the radial.

flanges I2 of the barrel so as to relieve the plungers proper from torque stresses.

In the form illustrated, the stationary reactance 'I is mounted for adjustment, as described in my copending application, to different degrees of eccentricity relative to the barrel while maintained with its axis parallel to the barrel axis.

The load transmitting elements between the plungers and the reactance 1, with which the present invention is particularly concerned, will be described in connection with theY dual cylinders 'B and plungers', which, in operative effect, constitute a single large capacity plunger and cylinder assembly but without requiring as large a diameter pintle and barrel bore `for the opening to the cylinders. Each of the piston head portions Ill is provided with a transverse bore I3 extending parallel to the' rotational axis of the barrel. Mounted within the bore `of each plunger, or aligned bores of ea'ch pair of dual plungers, and extending parallel to the barrel axis is a v load transmitting thrust pin I4, having a central diameter end portions Mb ,with extreme outer end portions Mc of slightly larger diameter than the portions I 4b. The pin is mounted within the annees bore It on capillary cageless anti-friction needle rollers I5, a spacing washer being provided be tween the dual .plungers for retaining them in proper relation to each other and for closing the adjacent ends of the plunger head' bores so as to prevent axial displacement of the rollers I and to form an oil retaining trough therefor.

'I'he rollers I5 are utilized as they provide free rotation of the pin about its axis within the bore I3 under extreme hydraulicloads. This results because of the free individual rolling action of each of the rollers I5, and because their small diameter and close spacing provides a large projected bearing surface between the pin and cooperating wall portions of the plunger head bore. Furthermore, their small mass, and absence of .races and vother accessories does not increase the the associated rollers I6, so that the shoulders' formed between the reduced portions and larger diameter portions Ila and llc define with the bores of the rollers I6 circumferential troughs for accommodating capillary cageless rollers I1 by which the rollers are mounted on the portions Ilb. If desired, slight axial clearance between the ends of the rollers Il and said shoulf ders may be provided. Radial shoulders I8 are provided on the reactance l for constraining the rollers I6 axially to proper position with proper operating clearances axiallyof Lthe rollers.

The radial side walls of the casing I are spaced slightly from thevends of the` pin Il so that the pin, mounted as described, is f ree to oat axially a limited amount. In order -to retain the needle rollers and plunger operating rollers and.

cooperating pin portion in assembled condition so that in event of breakage of the pin, these parts will not become disassembled, thev needle rollers may be more positively confined between the plunger rollers and pin and a trough assured for retention of lubricant for the needlerrollers lby the structure illustrated -in the smaller stage unit and the pump in Figs. 1, 2 and6.- in which the corresponding parts are designated by primed numerals. .In this4 structure, a pin Il' of constant diameter is used and the bore of each roller I6 is provided with an.enlarg`ed 'portion intermediate its ends, as indicated at; I S'a, defining end walls I6,sb. y The needle rollers I1 are received in this enlarged portion and constrained within fixed axial limits bythe end walls Iiilv.` The needle rollers I5' of the plunger heads may Y be correspondingly retained. The end walls l'b may be formed by press fitted washers if desired. 'I'hus not only are the needle rollers retained but circumferential lubricant retaining troughs are provided. For retaining the rollers' I6" on the pins, snap spring washers Ill are fitted into circumferential recesses in the ends 'of the .pins Il'. 'Ihe floating rings I 9' in this modifled structure may engage the ends Aof the pin, as do the rings I9 hereinafter described, but preferably engage the rollers I6" and are provided with radial shoulders I9'b at their. outer ends which engage the end margins of the rollers I8' and' .assist in retaining the rollers 4I6' in position.

Such shoulders I 9'b also reinforce and strengthen the rings I9', 'thus enabling them to withstand radial load and wear more effectively.

f In order to insure retention of the rollers I6 or I8' in proper operating engagement with the reactance and positive actuation thereof on the suction or low pressure strokes in case the centrifugal force is inadequate forthis purpose for any reason, reactance rings ljare provided. Heretofore, such rings as have been provided have engaged the rollers of the plungers sothat rolling engagement of the rollers with the rings as well as with the reactance was provided. This, however, results in increased rolling friction. All of the plunger rollers do not roll at the same speed in mechanisms of this character, as the radius of revolution of any roller is constantly changing and is different for each roller or I9' are free to float circumferentially, and suilicient radial clearance is provided for radial floating movement with the rollers and limited radial floating' movement relative to the rollers. 'lhe radial clearance between the ring I9 and l at any given instant. Consequently, a ring so lmounted imposes sliding friction on the rollers. lIn the present structure, however, the rings I9 rollers I6 is such that the ring I9 may be sub' stantially free fromrotation exceptrotation occasioned by intermittent light contact with the rollers I6 or when the centrifugal force is insufilcient to actuate the pistons outwardly.

Therefore, the rollers I6 are in rolling engagement substantially with only the outer reactance 1, and so are free from radial binding stresses' and subjected to less rolling frictional engagement. l

In order to vreduce any relativel rotational Vmovement ofthe rings Il, however, and to utif lize them also for retaining the rollers I6 properly positioned axially, the rings I9 are positioned y -to engage the circumferences 91 the end portions llc of the pins I4. the circumference of which 1 is'much less than the circumference'of therollers I6. Even if the rings I! were tight fitted,

therefore, their rotational' speed 'would' be far less than if they engaged the circumference of the rollers. Since the pins Il do notrotate with as great angular velocity as the rollers in the present structure, vthe rotation `of the ring I9 is negligible and continuous -operaltion at high speeds may be obtained without am' appreciable heatingfeilects beingcausedl thereby. It should be noted that the rings I9 are 'retained' in axial position by the radial Side-walls of the casing I,v the rollesIL-and, in some cases, by the re- .actanee of adiacent 'stage units. Consequently,

in caseV any rollerfll or roller and vlassociated pin portion isbroken'loose. both the rollers I6,

and the roller. pin and needlel rollers I1 inl assembled condition are constrained by the ring I9, the radial walls of the casing I, and radial flange I2 from. becoming jammed against other parts or broken and from becoming misplaced and wrecking other parts of the structure.

v With a structure auch as provided, it is apparent that free rolling engagement ofthe roll'- ers I6 with the reactance l is' effected. Due to the larger diameter of the rollers relative to the .pins Il. the rotative speed of the rollers about their `own 'axes is reduced for a reactance of given diameter over the speed that would be present were the pin portions Mb directly engaged" by the reactance. However. at high speeds, this reduction is insumcient 'and thereforel ntonly is thepin Il anti-frictionally mounted'withinv the bore'ril for free rotation about its own axis but the .rollers I8 are antbfrictionally mounted on the pin on capillary 'cageless `needle rollers I1, which correspond in operation and arrangement tothe capillary rollers I above described.

This results in a very marked improvement, rst but of lesser importance, is the fact that frictional resistance to rotation of the Arollers about their own axes is reduced. Far more important, however, is the fact that the pin does I not have to rotate in the bore of the plunger head once for each rotation of the rollers I6 of the reactance 1 is 100 units in length and the circumference of each roller I6 is one unit in length, each roller has to rotate 100 times about its own axis for each revolution around the circumference of the reactance 'I. If the pin were stationary the relative rotation between each roller It'and the pin wouldvbe 100 rotations for each revolution of the barrel. The same would be true as to the pin and plunger head bore were 7o than would a large roller.

the rollers I6 xed relative to the pin, However, the pin may rotate about its own axis relative 'to both the plunger head and rollers I6. Therefore, it may rotate tlfty revolutions for each revolution about the barrel axis and the rollers may rotate fifty revolutions.' Thus the relative rotation between the pin 'and plunger head is reduced to one half and correspondingly the rotation between each roller and the pin is reduced one half. Thus the speed of rotation of the barrel can be doubled without any increase in the speed oi.' rotation of the pins or rollersrelative to their sup- .ports over the speeds that are necessary in present types of pumps and motors.

By varying'the size of the needle rollers and and pressure to `be withstood as well as on the diameter of the particular rollers I5 to be used 1n` connection ltherewith. In general, however, the needle rollers for the crosspin need only be sufllcient to withstand the' load to be imposed thereon and of approximately the same length as the rollers provided in the rollers I5.

'I Referring next to'Figs. 4 and 5, a compromise is provided for use in smsller diameter or lower speed pumps'and motors. In order to further decrease the diameterof the reactance, the rollers, such as the rollersin the pump in Fig. 1, are eliminated. This permits further reduction in diameter of the reactance 20 and floating rings 2I. This is offset partially by the fact that the smaller diameter portion of the crosspin engagesv the reactance directly and must roll therealong and, since vits diameter is also reduced, it must rotate more times for each rotation of the barrel 75. smaller diameter than the hub section. The hub Itis absolutely necv portion is mounted in anti-friction 'capillary cageless needle rollers 24, corresponding to the bearings I5 above described, in suitable bores in the plunger heads, the'bore extending parallel to the axis of the barrel. The needle rollers, in turn, are retained in the plungers by suitable rings 25, press iltted into ,the plunger bores so as to form therewith a substantially unitary structure and a trough for retaining lubricant on the rollers. The end 'portions 23 of the pins directly engage the reactance 20 and iloating rings 2| for rolling relatively thereon. Thus the frictional resistance to rotation of the hub portion 22 is less than the rolling frictional resistancev between the end portions 23 and rings 2li even with the reduced diameter of the end portions 23. Consequently, rolling of the pins. on the rings 'is assured. The hub portion 22 and the end portions 23 are joined by a curved portion and the edges of the rings 20 are 'rounded correspondingly,as indicated at 2l, so as to provide arolling shoulder engagement for constraining the pins to xed axial position within the plunger bores while providing proper rolling engagement. By this reduction of the size of the pins at the ends, a

reduction in the diameter of the rings 20, and

in the diameter and size of all the parts of the pump may be effected and centrifugal and inertia forces reduced. By the use of the capillary cageless needle bearings, the danger of the pin binding in the plunger is entirely eliminated and an adequate load bearing surface is provided without appreciable changes in size andV weight of the assemblies. The rings 2| are likewise free Viloating in the same manner as the rings I9 heretofore described, so that free rotation of the pin ends is permitted while therings 2l may be substantially free from rotation.

Such arrangements as above described may be used in connection with rotary reactances in extreme cases, though the problems to be solved in rotary reactances' generally do not require such transmitting elements.,

It should be, noted that in the claims herein, reference is made to low pressure strokes and such term is 'used generically tomean the'suction stroke of the mechanisms when operating as-a pump `or the exhaust stroke when operating as a motor. The parts of the present structure not relating to the load transmision are reserved for inclusion in ymy copending application, Serial No. 22,259, led May 18, 1935.

having end portions extending beyond the lateral l limits of the associated plungers, rollers mounted on the extending portions of the pin for rotationl y about the axis thereof and relative to the pin, the said end portions extending parallel to the p in axis beyond the rollers, and reactance means in relatively rolling engagement with said last mentioned end portions of the pins for actuating the plungers on low pressure strokes and for retaining the rollersin operating position on the first reactance. Y

2.1n arotary radial plungergpump or motor including a rotatable barreLhaving a plurality of radial cylinders, valve means in valving cooperation with the cylinders, plungers in said cylinders reciprocable radially thereof, a reactance surroundingthe barrel for cooperation with the plungers in one direction of. movementl of the plungers, each plunger having a bore `extending parallel to the barrel axis, a pin rotatably mounted at 'its central portion in said bore for rotation about the pin axis, said pin extending axially beyond the lateral limits of the plunger and having reduced diameter portions between said central plunger engaging portion and end portions, whereby reduced diameter circumferential races are formed on the pin, rollers mounted on said reduced races of said pins and coextensive axially therewith, said rollers being in `rolling engagement with said reactance, anti-friction cageless rollers interposed between said rollers and reduced races of the pin and extending parallel to the pin axis and being constrained from axial displacement by said endA portions of the pin and said central portion, said end portions being positioned axially outwardly beyond the rollers, and reactance means in relatively rolling engagement with the end portions of the pin and in cooperation therewith for movement of the plungers in the opposite direction. f l

3. In a rotary radial plunger pump or motor including a rotatable barrel having a plurality of radial cylinders. valve means in valving cooperation with the cylinders, plungers in said cylinders reciprocable radially thereof, af reactance surrounding the barrel for cooperation with the plungers in one direction of mvement of the plungers, each plunger having a bore extending parallel to the barrel axis, a pin rotatably mounted at its central portion insaid bore for rotation about the pin axis, said pin extending axially beyond the lateral limits of the plunger and-having reduced diameter portions between said central plunger engaging portion and end portions,

whereby reduced diameter circumferential races are formed on the pin, rollers mounted on said reduced races of said pins and coextensive axially therewith, said rollers being in rolling engagement with said reactance, means on the reactance constraining said rollers to substantially fixed positions axially of the associated pin, anti-friction cageless rollers interposed between said roll- .ers and reduced races of the pin and extending parallel to the pin axis, and being constrained from axial displacement by said end portions of the'pin and said central portion, said end portions being positioned axially outwardly beyond the rollers, and reactance means in 'relatively rolling engagement with the end portions of the pin and in cooperation therewith for movement of the plungers in the opposite direction.

4. In a rotary radial plunger pump or motor including a rotatable barrel having a plurality of radial cylinders, valve means in valving cooperationv with the cylinders, plungers in said cylinders reciprocable radially thereof, a reactance surrounding the barrel for cooperation with the plungers in one direction of movementl of thel ance, anti-friction cageless rollers interposed be-l tween said rollers and reduced races of the pin and extending parallel to the pin axis, and being constrained from axial displacement by said end portions of the pin and said central portion, said end portions being positioned axially outwardly beyond the l rollers, free radially and circumferentially oating rings in rolling engagement with the end portions of the pin and in cooperation therewith for movement of the plungers in the opposite direction. Y

5. In a radial rotary plunger pump or motor including a rotatable barrel having a plurality of radial cylinders, valve means in valving cooperation with the cylinders, plungers in said cylinders,

and a rollerl engaging reactance for the plungers surrounding the barrel, each plunger having a bore extending parallel to the barrel axis, a load transmitting pin rotatably mounted in said bore and having end portions extending beyond thelateral limits of the associated plunger, rollers 1 `reactance means in rolling engagement with the pins for moving the plungers on their-low. pressure stroke. v

ELEK K. BENEDEK. 

